drm/bridge: tc358762: Switch to atomic ops

Switch the bridge driver over to atomic ops. No functional change.

Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230615201902.566182-2-marex@denx.de